Compiling PittNullCode is very slow on some systems (e.g. with gcc). I believe this is because files such as NullConstr_R00.F90 contain many whole-array operations that the compiler has to analyse.
I suggest to rewrite these routines, using e.g. forall or do loops. If we want to keep the elegant, index-free notation, then I suggest to add an elemental subroutine for the actual calculations and calling it with whole arrays.